The present invention relates to casting and molding systems, and more particularly, but not exclusively, relates to a mechanism to more efficiently interchange parts of a casting or molding machine.
One common type of casting machine includes four tie bars that guide vertical movement of one platen relative to another. U.S. Pat. No. 4,716,952 to Hegel et al. and U.S. Pat. No. 5,263,531 to Drury et al. are cited as additional sources of background information concerning such devices and their operation. To change casting parts for this type of machine, usually at least one of the tie bars needs to be removed. The process of disassembling a tie bar from the machine to change parts is generally very time-intensive and costly. Thus, there is a need to provide a quicker way to remove casting machine tie bars.
Some attempts to improve the removal of tie bars have included devices of the type described in U.S. Pat. No. 5,192,557 to Hirata et al. and U.S. Pat. No. 5,542,465 to Wolniak. Unfortunately, these devices are exceedingly complex, including multiple actuators and a large number of moving parts that take up an excessive amount of space. Also, devices of this type typically do not provide for the independent adjustment of a nut threaded on an end portion of the tie bar to accommodate changes in tie bar. tension while the tie bar is assembled in the machine. Thus, there remains a need for a better tie bar clamping or holding device. Preferably, such a device would facilitate turning a nut threaded on the tie bar to adjust tie bar tension.
One form of the present invention includes a unique casting or molding machine having a releasable tie bar clamping or holding mechanism. Alternatively or additionally, another form of the present invention is a unique technique to selectively hold and remove a tie bar.
In a further form, a mechanism has a pair of bearing members and an actuator. The actuator is coupled to each of the bearing members and is operable to reciprocally move the bearing members in opposite directions. Accordingly, the mechanism may be utilized to move the bearing members towards each other to facilitate holding or clamping of a structure and to move the bearing members away from each other to release the structure. This mechanism may be arranged to align with an opening of a platen through which a tie bar is passed, such that the bearing members are positioned on opposite sides of the tie bar extending through the opening. A nut may be threaded on the tie bar to bear against the bearing members and correspondingly hold the tie bar in fixed relation to the platen.
Accordingly, it is one object of the present invention to provide a unique casting or molding machine having a releasable clamping or holding apparatus.
It is another object of the present invention to provide a unique technique for holding and selectively removing a tie bar.
It is still another object to provide a quick-change mechanism for a tie bar. Further objects, features, forms, aspects, benefits, and advantages of the present invention shall become apparent from the description and drawings contained herein.